tools/power/cpupower/lib/cpufreq.h

   1 /*
   2  *  cpufreq.h - definitions for libcpufreq
   3  *
   4  *  Copyright (C) 2004-2009  Dominik Brodowski <linux@dominikbrodowski.de>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation, version 2 of the License.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 #ifndef _CPUFREQ_H
  21 #define _CPUFREQ_H 1
  22
  23 struct cpufreq_policy {
  24         unsigned long min;
  25         unsigned long max;
  26         char *governor;
  27 };
  28
  29 struct cpufreq_available_governors {
  30         char *governor;
  31         struct cpufreq_available_governors *next;
  32         struct cpufreq_available_governors *first;
  33 };
  34
  35 struct cpufreq_available_frequencies {
  36         unsigned long frequency;
  37         struct cpufreq_available_frequencies *next;
  38         struct cpufreq_available_frequencies *first;
  39 };
  40
  41
  42 struct cpufreq_affected_cpus {
  43         unsigned int cpu;
  44         struct cpufreq_affected_cpus *next;
  45         struct cpufreq_affected_cpus *first;
  46 };
  47
  48 struct cpufreq_stats {
  49         unsigned long frequency;
  50         unsigned long long time_in_state;
  51         struct cpufreq_stats *next;
  52         struct cpufreq_stats *first;
  53 };
  54
  55
  56
  57 #ifdef __cplusplus
  58 extern "C" {
  59 #endif
  60
  61 /*
  62  * returns 0 if the specified CPU is present (it doesn't say
  63  * whether it is online!), and an error value if not.
  64  */
  65
  66 extern int cpufreq_cpu_exists(unsigned int cpu);
  67
  68 /* determine current CPU frequency
  69  * - _kernel variant means kernel's opinion of CPU frequency
  70  * - _hardware variant means actual hardware CPU frequency,
  71  *    which is only available to root.
  72  *
  73  * returns 0 on failure, else frequency in kHz.
  74  */
  75
  76 extern unsigned long cpufreq_get_freq_kernel(unsigned int cpu);
  77
  78 extern unsigned long cpufreq_get_freq_hardware(unsigned int cpu);
  79
  80 #define cpufreq_get(cpu) cpufreq_get_freq_kernel(cpu);
  81
  82
  83 /* determine CPU transition latency
  84  *
  85  * returns 0 on failure, else transition latency in 10^(-9) s = nanoseconds
  86  */
  87 extern unsigned long cpufreq_get_transition_latency(unsigned int cpu);
  88
  89
  90 /* determine hardware CPU frequency limits
  91  *
  92  * These may be limited further by thermal, energy or other
  93  * considerations by cpufreq policy notifiers in the kernel.
  94  */
  95
  96 extern int cpufreq_get_hardware_limits(unsigned int cpu,
  97                                 unsigned long *min,
  98                                 unsigned long *max);
  99
 100
 101 /* determine CPUfreq driver used
 102  *
 103  * Remember to call cpufreq_put_driver when no longer needed
 104  * to avoid memory leakage, please.
 105  */
 106
 107 extern char *cpufreq_get_driver(unsigned int cpu);
 108
 109 extern void cpufreq_put_driver(char *ptr);
 110
 111
 112 /* determine CPUfreq policy currently used
 113  *
 114  * Remember to call cpufreq_put_policy when no longer needed
 115  * to avoid memory leakage, please.
 116  */
 117
 118
 119 extern struct cpufreq_policy *cpufreq_get_policy(unsigned int cpu);
 120
 121 extern void cpufreq_put_policy(struct cpufreq_policy *policy);
 122
 123
 124 /* determine CPUfreq governors currently available
 125  *
 126  * may be modified by modprobe'ing or rmmod'ing other governors. Please
 127  * free allocated memory by calling cpufreq_put_available_governors
 128  * after use.
 129  */
 130
 131
 132 extern struct cpufreq_available_governors
 133 *cpufreq_get_available_governors(unsigned int cpu);
 134
 135 extern void cpufreq_put_available_governors(
 136         struct cpufreq_available_governors *first);
 137
 138
 139 /* determine CPU frequency states available
 140  *
 141  * Only present on _some_ ->target() cpufreq drivers. For information purposes
 142  * only. Please free allocated memory by calling
 143  * cpufreq_put_available_frequencies after use.
 144  */
 145
 146 extern struct cpufreq_available_frequencies
 147 *cpufreq_get_available_frequencies(unsigned int cpu);
 148
 149 extern void cpufreq_put_available_frequencies(
 150                 struct cpufreq_available_frequencies *first);
 151
 152
 153 /* determine affected CPUs
 154  *
 155  * Remember to call cpufreq_put_affected_cpus when no longer needed
 156  * to avoid memory leakage, please.
 157  */
 158
 159 extern struct cpufreq_affected_cpus *cpufreq_get_affected_cpus(unsigned
 160                                                         int cpu);
 161
 162 extern void cpufreq_put_affected_cpus(struct cpufreq_affected_cpus *first);
 163
 164
 165 /* determine related CPUs
 166  *
 167  * Remember to call cpufreq_put_related_cpus when no longer needed
 168  * to avoid memory leakage, please.
 169  */
 170
 171 extern struct cpufreq_affected_cpus *cpufreq_get_related_cpus(unsigned
 172                                                         int cpu);
 173
 174 extern void cpufreq_put_related_cpus(struct cpufreq_affected_cpus *first);
 175
 176
 177 /* determine stats for cpufreq subsystem
 178  *
 179  * This is not available in all kernel versions or configurations.
 180  */
 181
 182 extern struct cpufreq_stats *cpufreq_get_stats(unsigned int cpu,
 183                                         unsigned long long *total_time);
 184
 185 extern void cpufreq_put_stats(struct cpufreq_stats *stats);
 186
 187 extern unsigned long cpufreq_get_transitions(unsigned int cpu);
 188
 189
 190 /* set new cpufreq policy
 191  *
 192  * Tries to set the passed policy as new policy as close as possible,
 193  * but results may differ depending e.g. on governors being available.
 194  */
 195
 196 extern int cpufreq_set_policy(unsigned int cpu, struct cpufreq_policy *policy);
 197
 198
 199 /* modify a policy by only changing min/max freq or governor
 200  *
 201  * Does not check whether result is what was intended.
 202  */
 203
 204 extern int cpufreq_modify_policy_min(unsigned int cpu, unsigned long min_freq);
 205 extern int cpufreq_modify_policy_max(unsigned int cpu, unsigned long max_freq);
 206 extern int cpufreq_modify_policy_governor(unsigned int cpu, char *governor);
 207
 208
 209 /* set a specific frequency
 210  *
 211  * Does only work if userspace governor can be used and no external
 212  * interference (other calls to this function or to set/modify_policy)
 213  * occurs. Also does not work on ->range() cpufreq drivers.
 214  */
 215
 216 extern int cpufreq_set_frequency(unsigned int cpu,
 217                                 unsigned long target_frequency);
 218
 219 #ifdef __cplusplus
 220 }
 221 #endif
 222
 223 #endif /* _CPUFREQ_H */